SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85adc7561f3f0dcaed677381b886e0801ff7475b97abaf54d0be578f38d4a614' 
  AND token = 'fIZ4VWHeDkGMZenqjKCkBG+CdEMf5G6J6mDspjbF04s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}