SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '790e793c64830edb7de57d1d4331061631733a4ea552645b0b09757c9a685cbf' 
  AND token = 'SqFCjb5FgeOXe/aHdA38ovIFl5oqA+a5RL3wZfMiOis=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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