SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec9801e4b8963d7d595ad3bc4bdb102c34c53282af42051c0ec1fd8abcbdb26e' 
  AND token = 'zc46LRBETPqAeMLsOZtLaGNcTerQXMdBt+6cuU73lWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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