SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '311f1bbd104596710d33f0397754498de8d45ffe4efc6af8b49d3d070c47cf11' 
  AND token = 'utqdbeqzzpyHHBnUESRJPOqyOGB/CcLpd31XcerdKWU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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