SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5d9cc9b7f8c8e5d1b967dc2bd632cd6d5eff80438eba743e41b7da24c585caa' 
  AND token = 'ynAki3JYIv/Vzhph905RRDW3RaiqJeEW2gVmtcvaLgU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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