SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a3eaee28b571e964fefb0144eade9e41000cead570f20858609133511493a46' 
  AND token = 'RT1O+Lyujx4JnRzzF3OSgtNN0BzgjE2Cj4Un9B/4tSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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