SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96342894d213328831fb85a8839fce315044d7dbc984da4fea039d0854cfc0df' 
  AND token = '6mTIUIgRZvGjmd2HKAvUyv11c+yf1T9gGlAicyoDQJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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