SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf4be6f42ff6b0a1bfb53b9d891c1f4697901730cb7f28dda6e80d4879dd77ea' 
  AND token = 'zKmnoKwUijsoS17digE1rXwCuD2G3rR+mIlWvT4iJD0=' 
  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"
    }
  }
}