SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b6fd0077cf04581d8e3cd9fb135529ff408af369084cb7794ffdd3b5b48145c' 
  AND token = 'RmcvwLKhJHtTkljw4kDnKCaqiWIUD7atR5hIsKGXMUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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