SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54c57f075f1948948beb2ae2003d3d75a05a13c32024fbfbf3a8d5cb1773538a' 
  AND token = 'zRbWrwz5aHtAN6mQtKUfVilzoXgDD22KjriS6RKx+yI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}