SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '776b5b988cd2069a0291d08b725ed663cc7485fbb782f70f2c12d96609f9a849' 
  AND token = '+gL/jXpSoRFyzW2s/5YwJRhIsC4vUiqZKUo1d5t+SYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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