SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '482831bbb7ce056c96ed018592868740345862cf05e4abcf3152a395cff2422a' 
  AND token = '1HSDCz6LpbWJl+LlpJTrHo9MuahvUgpKiJCMv/gaxEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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