SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd5d5db4d0c51235f4669a12a473c58bf40bd6c492da2e7f498640a791367917' 
  AND token = 'gvD3D/HdtWhy+Habj2QhTnvRbK+XxOBQQMm6DO69wbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}