SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79111e469de9bb368edd86b4699b30de6dc60cfec9fa3663d2c4675a48cb877b' 
  AND token = 'rteKr6b4wHzJB9+FouCI2WhrBXPl4Yqrlz+4roIBPBk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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