SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66c838e7f13cce6c8e740ec8394ff14af4f5d5519697e6a1ef1921666e430246' 
  AND token = 'ZV0ztLVQSYdkjXymtdwFjWwNC4lmEN77bijmdyPLQmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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