SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '431d68d4389b260703e828ae049bf010e339e6b78343a239f04670ecdf866a95' 
  AND token = 'qLvYcT1nKN8zZyMps4Uqh00JxcEXWzE42v/wknAeg+c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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