SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15bb60e328e7346d44fa3d5dafd43d0b24ad7431a6736db4cac0512c4b2169c6' 
  AND token = 'Dz6uJ9czzZc2utBauCxVtwp8fkbMCAlUdt7EejBh1Kw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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