SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2a35acb3e4ddf2cfbff21502147485f971e092720c052729af696ffbe3d163e' 
  AND token = 'O4ZLKODuzyHB28AKEzUsu9sNjchwc+KjpCNdfyz5Adg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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