SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48f3e27e5d4829cb0e4a0458d8449da91902bbf6601483ab6782c613787dddc0' 
  AND token = '54DwIN14oLfh9AqwhQ+8jsV0NK/zvmgbDYHZ4+SK520=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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