SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c20c8c0217e3469ac211f2f14bb306d293198dc1b741dc09cc84591883052457' 
  AND token = 'BA0Yj06txZDul3YQx6mP/Mb+JVp5VhW3/bR+YJSpq9g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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