SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea2558d294f9d707b486c3cacc2d915bcaef8563c8830555aba7d793d49ae6ea' 
  AND token = 'tOprvS3S0SdudqaCnTor9uzEuC4Ib+VkzWYmTbK2m1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}