SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '739fe982e943880646d0e5d960711b294c04c7f900f46234eabe965493cf43cc' 
  AND token = 'EZCBhtOLGlSFEKyOvUJzX5P2xIszxKW8rA7X9YaCXUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}