SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2ba0995034f919b0b26236a1919ea10f2699a38aa65ff2f69da95c134146034' 
  AND token = 'HTNNeZeTTlDh3AW0G8HlmkRRVlXrrzGvCjcW96kZu2c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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