SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efb6790c04c1930f52829f3cebaa079c912ed190a14785fa9fb62f8b63255d9b' 
  AND token = 'tcYA2dROkV6GqC89yxSSO4PL+WKtJYp907cAVcjelzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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