SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fcb15ee8b94ae06c0f74e2d7b8484ca53596d1bab2e51a2b1add10dae06a2392' 
  AND token = 'LyAtbW21veQ8bYfxJh7ZGmpbpXl76QAzEkphc0h7Zrk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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