SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c4187114af130e020056d8ca080bc27e38adf7e310d613acf03d3c01d54a25e' 
  AND token = '5Kgdw/SjClSuGry1BiJyo63Vw6pRu/sogABkYmH4bVI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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