SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c8239c88b15745f97c392da82cb53da3f4d598983666cdb9b2889edfb6cdf413' 
  AND token = 'e+cNQvmrmDfPqMQZ6NOF0HRwAHh4fwZ+DL+L+KhwPgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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