SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2bb7724d2aa4ac1c59769ba9bfa42b83f5ae5835835c4e00ca41c084279f9ff' 
  AND token = 'GmaoOjd/7PmaZpvl8Eh+qlSdkSB2YHkgSkIyhp6FKhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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