SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5608a293dbfb099d0b846f2eaebc1102fdaba75c771364a8ab5ba046428bcd51' 
  AND token = '1fHcLhPsL+4pZqbCB2t2VnABxtp5xaYDS0xPopDQ3RA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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