SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6836e690eee29b774b3acfa249a9623ecfa8ab46397d987c6c7a2dced7ad0d64' 
  AND token = 'G7JOk2Tr5uOmXIJDz3R+EyjZCW+9xGIxdpynyCOXSS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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