SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b76bebf249d287df8197758db67333cbc53b6690791634120d5ea86b972c0309' 
  AND token = 'h8ksq4ZvwL4SOr2+zHBpV69voF+OoLZoL6lyJwRPGhw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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