SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e8d8aedfafbbce1ff6053320274fffbaf444e278ced5aaa4dc0cf9eeac67af2' 
  AND token = 'se4QIkAGcZKbYUPU5/5XVRJp/PbbSTdbLnN8Vft65PU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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