SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '471114c0dae5482643944be52d4dfad01858ce89f94eaa2e180c29f7c7f1d64a' 
  AND token = 'UnB2IP9P2eoAOfyWnGbWWdjHlNJWjK/ZYvuTSxk6uYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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