SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '292c36b92128e3b4846740fdfd4cd350969fdc96a9627406615f4049a766a610' 
  AND token = 'MIoulMY3rcSRrmjQbH3ybo1cB4mnStgNnYZlKzted8o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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