SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a8958044acde9c01ac7755172024196deb516f260526db21953691ecd3be211' 
  AND token = 'A8CwsAU1vmUj8rD3je9EjTiU4saIGczKuEC+dlqclco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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