SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a9d2bd527adc5c3f76257b741f5eaa6039a2371f5b0ffe7b2925064bcde7b46' 
  AND token = 'PeRRdqWiRZOFPW7sKXoHhShAJzVUg+JI+/QQGui8r3U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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