SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2ff2fce75db3b1d044f942e9c24d5f0355c00385be44941e790eb3c10dd043d' 
  AND token = 'ZaUCQO9UcjWlubsMoNQxE1TYNPBvf4NbuONIfMIV7qo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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