SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c33eed4c4bf0477d8e2413689da966edf98a1daa9887859b7f15e38865be55f3' 
  AND token = 'kNIlmB5b0oQrP2LjQHpg/pRIE1xXMy+SFgT0L9ZfhlM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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