SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7453da91b74372f09012701bfdab7c64a5b534b1327662f52ae095a297674a7' 
  AND token = 'aI6iTZdYx/njLqHjcBCpELOHx+huPBZgC1hkCCNUFx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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