SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0e46f0d9058a34c44c95c4e400979724d8a8dd37de290b199a4e625a501f689' 
  AND token = 'h6R6UHyhHROVmdMlpySEgfFpNB8HJDB9cz/7/sOVHC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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