SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33f51fd1a74663bcfa23bd51b3333d39cfd3c13c8a3b08c63910457f2187ab3b' 
  AND token = 'VT1gKEFntVJ/2hF1ABemZrz/rGZjMRYZ5HwF8cHXiwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}