SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b66f32d5aecbcbd45f30b593080aff3739a231b0e24885c350a2831906f8cf9' 
  AND token = 'tXfWHIDTgZNZ8UQjRWVNEgGbv5dg0shA8LjoRT1g1O0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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