SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96c77303effbc7aceb5078622a5d49a04309f580f30ca9097b8bae56ee07393d' 
  AND token = '0d3VGUdhXfbD1ORnNVDBNX2ORJmj0icCstf9/2Apadk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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