SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3382e7771832a345c08fd964cf320c37fcd8c76533cc37df3baa47e52a702c82' 
  AND token = 'O7aRDKMkzgsUTh+p9IDBHGk3tff50EShhcHxgeOF7Rs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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