SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19337e5250e78fde4a01c8a1c0a2ba5ac3d9886c68790b6d7af1c646e84da1b4' 
  AND token = 'NTWmwWljhobT//oOLxFMhsxAvCGKSvC+6ZjeCIB58q4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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