SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f08f0d8021ddd2f1a11fe25fc9fef2d2acd67f1e392debce11792b75e31505d5' 
  AND token = 'EhZP++zRqEbjM1YS1inMkfb/VpRMhUN+exyyYyEAe64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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