SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd4808632cd6651c1ef2fe2025bf6fc6b37e82bd98f129a45a30e82f3793467d' 
  AND token = 'hQKzmZrbI09loQvcrhvhgD6kKOfqbS2AU1hROpGEkuE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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