SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9b1451b594c781bfa36b529b78c7f33bfdfc0c09e994da740df3eff358ecd9b' 
  AND token = 'Fa2nEXsNOG2HzJsOOGTCNQrsCaOJ5d9DdfqHrssgc+c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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