SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c418150fe07e50fbacaed3d7a0be9e550e91d7a5c6af7238833142adacfd882' 
  AND token = 'Ir+hZ0avQ2UN1GavxCZF+DslD5Zsz+xsIbmPWntvTPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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