SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '620db37b299db60c8db0d900da98ca752fbcd8c4a36f04b2ba0f2a0471a46952' 
  AND token = '3xH4p8FMSboEFi/eNCgq1NaMuZr/gwbGfzdpNTerDA4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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