SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd76af6fedb9056586be3e56dc92ce9399e090b334ddff1d13183822aab9427e5' 
  AND token = 'lUxsCpgJl+tQpe1r5p2iKn6iSwopBUK1gQxAaPUknvI=' 
  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"
    }
  }
}