SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '039a0a105626f13da9a56888dc6e3a3d6254c172aa561a078c94106fd985ec05' 
  AND token = 'Y7bUYRd80Kqjwe5AeG7dgIJ9Frogt7pKqNS4OtPGmfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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