SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b50ccb4d4f6cf57c325cf85bb4206510734cc1536dff96034ead68a6a87e5e79' 
  AND token = 'O9cJ2ZiigAV5blV/jTRGsguXHKmAwR68hX1ImI0mqZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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