SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5f407c334b129c8ec64eebb651f9dd4943d5a39496b0c870f52644a0a8315c9' 
  AND token = 'ijfMOxcqVjFYrzG+sRnR5KawSSmzTZsYeIjy/8QY0Cw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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