SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f83049a2cd75bdf158b3d90cda6e6b0525b817c341244273aba3215223ae9df2' 
  AND token = 'UItVLXTinPQ7PFv6NIJD6mxAFU6/QA89D+U4IpPvzuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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