SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91ca99ede5e78ab5bf3114c621c49b601d753bc75a560a52c7348d525fa32263' 
  AND token = 'WtyZmd19jXZP8eArAFld0/0tFSv16eItLSsOp2Xo6BM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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