SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9691f0eaaa6fdf7ef3a58b0c834983f4255b5c530d8db67572f88d2f3e905b5e' 
  AND token = '0hY2voG2epAVuiu9HT6yKTc/+z6ZSOyiqRJRhUBvM+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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