SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ef61387211c48a3d3d2d71d880fee1ee07afd0013f9c14b4342bacf98a768a1' 
  AND token = 'KWE41cCtiRNbqwut/z/QL6vfAHzYq1WjH0aCaVtnT5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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