SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0153f7473f993aeda41981599da57f4e6a9fe28611fdd6b2b63028da640a9f5' 
  AND token = '/Wfgu6nl/szmx0hSnajNdUUv+SJCO1Zf5XUKc+3MTH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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