SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '742074ac95e7e26ae6f54b84e14bba76a4de2ae0c1221f56358258164202e174' 
  AND token = 'WqJA9469AoKDqBVHslIEZoW86jKdL8EosXrZaEKFtec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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