SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21625cf7d5834291b4861ec8136a74d611cdc22db2b287b1ffcf372b396c71a3' 
  AND token = 'QqvGKDYy3+yfyDxNpPChHIgksZmpSotdUXL5V9DtiYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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