SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf8a7bc48ae3dca2571d7f522c2080b9462356160d128ad8564b4816648a89ff' 
  AND token = '4jlMXIDQ6ocWBDzEme9hFIo6bWQLh+HPi8gggpdS+kA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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