SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dc484eea3e3447523d022b1a2724d33c4e879a996221b478d341a659142a0da8' 
  AND token = '4gXkahl1jb1fyVeFuEOVgu8T1vocg4exee+v1W9yIUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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