SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '02b6bcb2ac10e84575eeae323a3ae75af8400cfe5b073e45740d324243982596' 
  AND token = 'jagQjpDMYMLjUIxHy+YQJriNszJsDRbZcCrEp6+d/JE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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