SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e587183cf60a16b752f7a4bcc072789164e80cb93475f663887733382b00766' 
  AND token = 'l7m9TRAwgJfaqZ9fC43l30g65TuoUWlJZzMSDNeKG4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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