SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '612f6e73ff91f4016111482763c03860c3d7240f628f9f3b6dd946f915abfca3' 
  AND token = 'O45CinMb0NQHw2F1dtcnThdXj0Nfx9xWHof0Zr1TIbE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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