SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f9f8f8b0f19a7f1e3d400a2b6893ab207f256c6356ba8b9e3a1a5e6f94864eb' 
  AND token = 'hLTzxR0wVjA36w4AwK5MuHn2loCFqcWtHcOGxLOogbY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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