SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd33e3cda30cd72ea0ccbede6e86a604d8a415f163460409c5c4ee0d7a1aad5cb' 
  AND token = '5tvPcQwdd+sbuR8GxUe6xilHvt5GT2IF+NWjveS6zI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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