SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ad38c1b43490dc45892c6b27b39c00c13902d90345985fb20db0b24af19e068' 
  AND token = 'B6yRqXoziTcCqXLigLAqH4E/xCAcxMAhQGSJIauBWyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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