SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bcb8d9053da0b716af111f17de9267bf66af8689f59ec2aa3e0d7c8279a06caa' 
  AND token = 'XolcFP41POtvGWBcBZGQ/aM+ga5J8/3opjE7TpDYz3g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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