SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f3108c306048ad89d12ce93e5069dee57dc1fc80cc1273e9057e9387f7691de' 
  AND token = 'tSccwx/t/3nS/ZFMk2z36tmL0zMnuQ9wLk9MsLAW27k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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