SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c5907890ed3d04f525729a0bb54c836dfdc6c314e4a69b65030b39dd813e382' 
  AND token = 'PvT/NyNpB+ia7KQgW7xrfXvcQEiUTNtUnmcYZz7Bkmw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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