SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d90c1008137b2f07cbd96de5a9e8d73a87dcaa98485186fead659e05105a4b7' 
  AND token = 'UMRjzGHExb1qPoNgPHdupbaZEYjoRwIp3VSEPeW4Edw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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