SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36ef377718e4a235122abe797e9260489f53837e022e5053ce8ebc4a541a9369' 
  AND token = '+F15cJQb/UO1C6ml3LucfxuIVG1SyFlayMHgvYMbNUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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