SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ba8ca834b0ba6b901af4ff6b821536b6becaa077d84d3257e6c3e92c06ff7ec' 
  AND token = 'mKeh2nYBnhxOp2mDsROB+RulrXloTzpfJv9ae2w/kVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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