SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a120eeeb0103488ca9c0d404c9d2790982923e863a8191301040406d8eeb4027' 
  AND token = 'EYJxUGf9imYgCLUPkO0mpDzPc1Iugc3w2gFEvBw7ykM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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