SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc937e30757d54f5de53bd30f9900ea9c5e1d7991fd8d2c6ad83fce0e8eb807c' 
  AND token = 'mMigats+II5bkgFkaqwx06NmbldtwNK19+kkun2avtU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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