SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '281f5f6c4d199802566c076c2517bedb59d056ae289bfd2834c8dea0ef5af7b2' 
  AND token = 'ZEmlDaof1gs6m5CQqxLS1S9/gfKXJGLnIJaU1/MhcdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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