SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a306cdc1c457f1427cfc69f9403683fa367733e92d6f85629d184f4be09bd567' 
  AND token = 'KggxtoJspq3zdfhFCaNmBKZzZRgSUx3gbFMSAq0zsxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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