SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43b7a6e426bc5aa319445a472c2ab6fe1823c6c797d793165e1c07e9bc9e9e57' 
  AND token = '7SA2WSUQ0ELojATatSsETZpANP0OhT4RWoKD8KojxHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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