SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd8a21aa6f49466a6de18bcd53cfe2edb079477502bb5c710fcb587a681ebc370' 
  AND token = '+iAU7Pqb2dbaU7wjjZ/EfUyaRm3kWpdhgxKT4bXx62g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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