SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e70f6595ee1c17588acf70e4c80a99248067126145e240f9ea0db4e7118bbb8' 
  AND token = 'fPNFbS7JNHpNcXGVEMmVL2+mYOn/gHHprHA3sm8IF3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}