SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '019b7e908d19b11d97f1ee59412ce90e42c3b07dc245275a304308652620f1f3' 
  AND token = 'Z+9ijxBYucOZ0n/Q49Vw45hcd7+jlz5sk/bZ7qAylGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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