SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ff2f11aa2d3eb0c31cae6f97078426c909acd83526852a141a541662950d46b' 
  AND token = 'nagu1chCx+tlYKUjbXARpep3Z1uQkNBIvgnG10qL3bI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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