SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8393d600ba0f2520c202f3cb927c52a1e91f4a75eaf3dcc906edc420f0344897' 
  AND token = 'eV9Bdchw2G6c5JgOCfF1W/UbMRzBGIogvY/+LMwvQnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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