SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b06fed1686ec16462b41f8f937e1c899b81d029d05690051959b83d3c5fe3382' 
  AND token = 'uPuZKNSND+7cJHB6h94cJGF9N4rpjh7qOTMChz0Y+Ow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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