SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c0ef5c8b180a62b35fe2882330a2f56b72ea9c0bfbcca0997ad6e340a464633' 
  AND token = 'V/iCaG49lSvvpdwOz+wS2jlvfA+3qWSd8/Zvy+l+gtQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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