SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'feecdbb54b4f9e186a1d5d74fc9c93ade77e62f5f2af458a22b9e5102a1c3a03' 
  AND token = 'LjdRGbfYf8nbyHf+prUR2KCSt53sbGG91bEha4bxp3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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