SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '868ecdcfe1182c978646b8453a617e22958763826ddaab37eefaea57cec8c046' 
  AND token = 'beG5NtxujcZ26yXeuuGpRjBq14tKk+4qVMOKSVuQf+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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