SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ccabe8ff96eb21da5799baec9138291a35fbd86c86f0fe28b2e3abe6c28a82f' 
  AND token = 'KRy4ZQp+z2LmgZRmy8dEClAeun3AmdNlOC3Lma4XHZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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