SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27f959f0755ef9fe37e89ff9c0a9252ee7a8b9a6773bffda6977d47b94499069' 
  AND token = 'H2EOhFowRCE4yvHeBfmTLw8VvqIDPSSNflZtV2aH7qs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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