SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74d2b67b3b55dcc5e9aacf46622e0230b58fe72afcbc21d1501a8ea4d898b690' 
  AND token = 'RMGKYvKiXxyFvwmY8jlFEJdlq2/2Di+OLPlthjj/5yU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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